The focus of this Research and Training Center in Hearing and Balance is the study of labyrinthine from the biophysics of hair cell mechanisms to the rehabilitation of patients with unilateral hearing loss. The research we propose is focused on three closely related areas: mechanisms of hair cell damage; testing and rehabilitation of patients with unilateral vestibular lesions; and signal processing in the brainstem auditory system. One group of three projects focuses on in vitro and in vivo studies of these mechanisms of action of pharmacological and environmental ototoxins and on ways to mitigate these effects. A group of four projects attempts to devise better ways to evaluate otolith function, to learn more about vestibula-ocular adaptation with implications for the design of physical therapies, to examine effects of anti-motion sickness medications, and to test the efficacy of physical therapy on improvement of vestibular function in patients with unilateral lesions. A final group of four projects focuses on the role of on and of other sensory inputs on signal processing in the cochlear nucleus. Our proposed training program will integrate training in hearing and balance and will provide for strong interactions between basic science and clinical trainees and faculty. This program takes advantage of the Hopkins strength in basic and clinical science. Among a number of novel features that build on an already established training program are the development of a clinical rotation for basic science trainees, an integrated research and clinical residency for selected clinician scientists, a neuro-otology postdoctoral program for otolaryngologists, neurologists, audiologists and physical therapists, and a sabbatical plan to bring scientists and clinicians to our Center from institutions with inadequate research environments. We propose a series of continuing education symposia in hearing and balance for health professionals that will address important clinical issues with a firm grounding in basic research. We will offer a continuing studies course that will make current information on hearing and balance function and disorders accessible to the local professional and lay communities. Finally, we propose to develop a broad information dissemination program to reach health professionals, the lay public, opinion leaders and patients. This program will take advantage of the extensive Hopkins Public Affairs machinery.